Diaporthe phaseolorum f.sp. meridionalis causing extensive soybean losses in Brazil
Diaporthe phaseolorum f.sp. meridionalis (Diaporthe phaseolorum was deleted from the EPPO A2 quarantine list in 1992-09) has been identified as the causal agent of soybean stem canker and represents a new, aggressive variant of the seed-borne fungal pathogen complex Diaporthe phaseolorum in Brazil. It is regarded as the most important problem in the soy-bean crop in Brazil at present. It has been first detected in the growing season of 1989/90 and has since spread to important soybean production areas of the countries. Yield losses up to 80% were reported and data from the 1991/92 harvest showed that in some regions of Parana estimated losses exceeded 4 million USD. The pathogen is usually spread by seed and seed infections are usually less than 1%!
Sources
Blakemore, E.J.A.; Jaccoud Filho, D.S.; Reeves, J.C. (1994) ;PCR for the detection of Pyrenophora species, Fusarium monoliforme, Stenocarpella maydis and the Phomopsis/Diaporthe complex.
In: Modern Assays for Plant Pathogenic Fungi. [eds. Schots, A.; Dewey, F.M.; Oliver, R.] CAB International, Wallingford, UK. ISBN: 0 85198 870 9